You can bore the cylinder and install a S65 piston, rings and wrist pin but you will have to file all around the top edge of the piston so it won't hit your head. This does give you more power. There is no need for rejetting or needle adjustment with this mod. I did this to my C110.



Better option is more power and a fourth gear. You could go with a Lifan motor. I wouldn't go past 110cc and would probably choose a 90cc.



Or...maybe go with a S65 motor or a CL70 but these are manual clutches. I think you can install trailbikes 88cc bore up kits on these two motors but I am not positive.



If you do go with the Lifan I would like to hear how you like the motor. There is not a lot of reviews after the install of the Lifans.

 

CT70 bottom end with the tb88/race head kit is pretty potent.

 

thanks for the info guys. ive thought about the s65/90 motors. but they're hard to find. the piston swap seems like a cool mod.



i actually have a brand new 125cc 4-speed semi-auto lifan sitting around. my girlfriend wants me to put it in the c100. but i just cant on this bike. we spent the last 6 months building it, and i'd hate to put a non-honda motor in it. and im ok with building a ct70 or z50 motor or something like that. nothing too crazy, just like nice piston kit even a nice head/cam



heres the bike so you guys know what im dealing with

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Very nice!!!



my friend just bought one and a ralley tank and seat for it, actually he bought the tank and seat and had to buy the bike to put it one,lol. He is planning on a lifan 125, but it may be a little before he gets it done.

 

Clean Cub



I do not know if that 55cc pushrod engine has the same mountpattern as the ohc 50's otherwise a Cub90NT engine (semi 3speed) would be nice.

 

I've never met an engine yet that couldn't be bored a bit, head cleaned up, cam reground

 

I've never met an engine yet that couldn't be bored a bit, head cleaned up, cam reground

YouTube - 1935 Maytag Washing Machine Engine

 

YouTube - 1935 Maytag Washing Machine Engine

Piston port dinger? C'mon, Ricky, gimme a tough one

A little port & polish, bend the governor arm to fire more than every third hit, my PeeDubya Jemco low pipe with stinger tip, an 18mm Delorto, Husky chainsaw piston, some castor oil in the premium... Sure, it'd shred the Hell outta your clothes then, but would sound and smell sweet doing it



Now quit dinking around in peoples threads. We just got chastised for that a couple days ago.

 

Piston port dinger? C'mon, Ricky, gimme a tough one

A little port & polish, bend the governor arm to fire more than every third hit, my PeeDubya Jemco low pipe with stinger tip, an 18mm Delorto, Husky chainsaw piston, some castor oil in the premium... Sure, it'd shred the Hell outta your clothes then, but would sound and smell sweet doing it

I had a twin cylinder opposed one of these when I was a kid to fool around with...it ran...just never done anything with it

 

I think the idea of getting 45-47 mph, no wind, out of a pushrod 55cc motor, is pretty farking impressive, and that bike is lovely.



I think any changes you make to achieve 55-60 mph will result in losing some of the character of that bike, whether the engine originates from Honda or not. You'll be making mods that involve a more nervous, revvy, noisy, increased maintenance engine. Fatcaaat has some Youtube videos of a wildass CL70 he built, going through the gears to some extralegal speed in a city setting, and it's impressive, but it doesn't sound relaxing to ride. My point is, if your girlfriend wants to be able to achieve 55-60 for her riding conditions, a creampuff classic like this is not the best bike to do it on. Save this one for slower streets and instead of dropping a crazy motor in it, buy a used small commuter streetbike that's comfortable at 55-60, not maxed out and beyond its chassis design comfort zone.



If keeping this one running for daily use is a priority and is turning out to be difficult, due to a scarcity of 55cc OHV parts, I think that would be a better reason to consider an OHC swap. Possibly with mods to increase performance somewhat. But do you really want to see some hi-flow exhaust, an open-element air filter, an oil cooler...stuff like that dangling out of that bike?

 

Well put.

 

I think the idea of getting 45-47 mph, no wind, out of a pushrod 55cc motor, is pretty farking impressive, and that bike is lovely.



I think any changes you make to achieve 55-60 mph will result in losing some of the character of that bike, whether the engine originates from Honda or not. You'll be making mods that involve a more nervous, revvy, noisy, increased maintenance engine. Fatcaaat has some Youtube videos of a wildass CL70 he built, going through the gears to some extralegal speed in a city setting, and it's impressive, but it doesn't sound relaxing to ride. My point is, if your girlfriend wants to be able to achieve 55-60 for her riding conditions, a creampuff classic like this is not the best bike to do it on. Save this one for slower streets and instead of dropping a crazy motor in it, buy a used small commuter streetbike that's comfortable at 55-60, not maxed out and beyond its chassis design comfort zone.



If keeping this one running for daily use is a priority and is turning out to be difficult, due to a scarcity of 55cc OHV parts, I think that would be a better reason to consider an OHC swap. Possibly with mods to increase performance somewhat. But do you really want to see some hi-flow exhaust, an open-element air filter, an oil cooler...stuff like that dangling out of that bike?

+1 that is a nice machine and it would be a shame to distract from its original beauty

 

Piston port dinger? C'mon, Ricky, gimme a tough one

A little port & polish, bend the governor arm to fire more than every third hit, my PeeDubya Jemco low pipe with stinger tip, an 18mm Delorto, Husky chainsaw piston, some castor oil in the premium... Sure, it'd shred the Hell outta your clothes then, but would sound and smell sweet doing it



Now quit dinking around in peoples threads. We just got chastised for that a couple days ago.

Stand aside, heeeeeeeeeeeeeeerrrrrrrrrrrrre's...CAPTAIN PEDANTIC!!!!!!



Maytag engines are not, in fact, piston port. That one has a reed and breathes through the crankcase, and a completely un-counterweighted crank, and a brass rod. The opposed twin ones use a hollow crankshaft section as a kind of rotary valve.





Regarding the OP's bike and FP's original comment, what about a bore increase and port cleanup on the stock engine? You could up the torque an hp a bit without sacrificing reliability, I bet, and you'd still have the old-style engine cases showing, and could maybe retain the stock filter, carb, intake and exhaust...and still see a little more top speed (or the ability to pull a slightly higher final drive ratio).



I think I want a poster of that bike. Or make it my computer desktop background, or something. That is really nice.

 

Good idea on a mild hopping-up of the stocker.



Re-watched with bifocals, see reed setup now, Schnurle-head Bend them stops

 

There's a reason why that bike will only top out so fast (and I"m pretty sure 47mph is being exaggerated by the speedo). The reason is that the suspension and brakes won't support the extra speed.



Case in point...the honda passport. A 70cc motor is fine on them for a nice 45mph. But when you put in a 12hp beast that can go in the upper 60's and you hit a bump it throws you all over the place. The brakes are ok if you are less than 160lbs. What I'm saying here is that instead of butchering up this beautiful bike you did so you can go a little faster...and so you can avoid updating shocks, brakes, etc....



Just build something else. use this for cruising and street rides and build something that you can feel comfortable on at speed. YOu won't feel comfortable on this at 55mph...that I can assure you.

 

I got a couple Maytags, one disassembled, if you need to see ignition cutout (no governor bending needed...just change spring tension!) or other internal spy photos for your new line of hotrod vintage washer motors.



So, Rathead...where does a C100 restorer go to get mechanical wear item-type parts for one of these things? Who specializes in pushrod engine parts, or carries them, etc.? What are the really hard things to get, vs. the easier things to get? I'd like to know more about the fixup process on this thing.

 

Clean Cub



I do not know if that 55cc pushrod engine has the same mountpattern as the ohc 50's otherwise a Cub90NT engine (semi 3speed) would be nice.

i havent tried to fit another motor into this cub. but a friend did a lifan 140 into a CA1xx(super cub with the toaster tank) and it required very little frame notching to fit.



the lifan motor ive got fit right into a 81 passport(c70) with zero modding to the frame.

 

thanks for all the info guys. deep down inside i dont want to pull this motor out. ive been trying to talk her into just building a crapy passport up(thats what im doing now for myself)



but this still dont change the fact i want to build a motor for mine

it seems the crf50 motor has the most mods to buy. or a monkey motor..... what motor in the states is close to a jdm monkey motor? i'd love to do a 124 takegawa dohc build for my bike.........

 

I got a couple Maytags, one disassembled, if you need to see ignition cutout (no governor bending needed...just change spring tension!) or other internal spy photos for your new line of hotrod vintage washer motors.



So, Rathead...where does a C100 restorer go to get mechanical wear item-type parts for one of these things? Who specializes in pushrod engine parts, or carries them, etc.? What are the really hard things to get, vs. the easier things to get? I'd like to know more about the fixup process on this thing.

the hard things to find are nos plastics!! like the light bucket, front fender, legshield...........

for the most part ebay has alot of stuff.

but for the hard to find things, my girlfriend got the nos parts from ohiocycle. hes got a long list of nos parts. she got the light bucket, front fender and brand new speedo from there.



a good site for little parts is Honda Motorcycle Parts, Kawasaki, Suzuki and Yamaha Motorcycle Parts - ATV, Classic Bike, Dirt Bike Parts

i got things like nuts, washers and the brake and speedo cable there.



the engine i havent really got into yet. i got the shifter seal and kickstart seal from bikebandit. and the only other thing on the engine i got was a carb rebuild kit. got that from ebay.

 

That is a really nice cub! I think any OHC motor you install you will have to slightly notch the frame and since you have already done a nice job on the paint I can see why you would be hesitant.



Speaking from experience....I would definitly go with the S65 piston. It will give you more power and you may be able to add a tooth to the front sprocket to gain more top end speed.



It is by far your cheapest option and can always be undone to return the bike to stock.



I have a S65 piston in my C110 which gives me better climbing power and I can spend more time in fourth gear. It also helps on windy days.

 

DON'T TOUCH IT! You have achieved perfection. That is just outstanding. Beautiful color choice. Seat and whitewalls are perfect. I love your bike. Am I gushing?..

 

That is a really nice cub! I think any OHC motor you install you will have to slightly notch the frame and since you have already done a nice job on the paint I can see why you would be hesitant.



Speaking from experience....I would definitly go with the S65 piston. It will give you more power and you may be able to add a tooth to the front sprocket to gain more top end speed.



It is by far your cheapest option and can always be undone to return the bike to stock.



I have a S65 piston in my C110 which gives me better climbing power and I can spend more time in fourth gear. It also helps on windy days.

Chimp, did you do that S65 mod to a OHV Cub motor? I ask because looking at the thread below:



http://planetminis.com/f14/c100s-sale-159544.html



I see the Craigslist ad there has two different Cubs in it; the red one is OHV and the blue one is OHC. Certainly a S65 mod would be easy in the OHC one, but I thought it would be good to clarify this in case Rathead decides to scour the country looking for S65 top end parts...

 

I put the S65 piston in my '63 C110 which has a OHV pushrod motor. It is the largest piston that will fit a 49cc pushrod motor. The top edge of the piston DOES need to be filed for it to work or else it will make contact with the head. If I ever buy another C110 or a C100 I would definately do the S65 piston again. The boost in power is well worth it.



The ad from craigsist shows only one C100 the other is probably a C70 or maybe a C50 which uses a OHC motor. The seller made a mistake in his ad.

 

Thanks for the info; good to know. If you by any chance have photos from when you had that OHV motor apart, could you please post them? I have never seen a OHV one up close (other than a QA50, which looks like a different top end to me) and would very much like to see what the insides of one look like. I've seen exploded diagrams but photos would be really cool.

 

Sorry, I don't have any pics of the motor opened up. The internal cam and the pushrods are kind of neat and some say this design is better than the OHC motors but I disagree. I think Honda went in the right direction with the OHC...they are much quieter and can be revved higher. I have blown two cam gears. One last summer and one this summer. But I do love my C110.